Add FDPIC info into image_info structure since interpreter info is on
stack and needs to be saved to be accessed later on.

Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>
Signed-off-by: Christophe Lyon <christophe.lyon@st.com>

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 7ba3795..363da67 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -287,6 +287,23 @@ static inline void init_thread(struct target_pt_regs *regs,
     /* For uClinux PIC binaries.  */
     /* XXX: Linux does this only on ARM with no MMU (do we care ?) */
     regs->uregs[10] = infop->start_data;
+#ifdef CONFIG_USE_FDPIC
+    /* Support ARM FDPIC.  */
+    /* As described in the ABI document, r7 points to the loadmap info
+     * prepared by the kernel. If an interpreter is needed, r8 points
+     * to the interpreter loadmap and r9 points to the interpreter
+     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and
+     * r9 points to the main program PT_DYNAMIC info.  */
+    regs->uregs[7] = infop->loadmap_addr;
+    if (infop->interpreter_loadmap_addr) {
+        /* Executable is dynamically loaded.  */
+        regs->uregs[8] = infop->interpreter_loadmap_addr;
+        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;
+    } else {
+        regs->uregs[8] = 0;
+        regs->uregs[9] = infop->pt_dynamic_addr;
+    }
+#endif
 }
 
 #define ELF_NREG    18
@@ -1692,6 +1709,11 @@ static abi_ulong loader_build_fdpic_loadmap(struct image_info *info, abi_ulong s
 }
 #endif
 
+int info_is_fdpic(struct image_info *info)
+{
+    return (info->personality == PER_LINUX_FDPIC);
+}
+
 static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
                                    struct elfhdr *exec,
                                    struct image_info *info,
@@ -1719,6 +1741,11 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc,
         if (interp_info) {
             interp_info->other_info = info;
             sp = loader_build_fdpic_loadmap(interp_info, sp);
+            info->interpreter_loadmap_addr = interp_info->loadmap_addr;
+            info->interpreter_pt_dynamic_addr = interp_info->pt_dynamic_addr;
+        } else {
+            info->interpreter_loadmap_addr = 0;
+            info->interpreter_pt_dynamic_addr = 0;
         }
     }
 #endif
diff --git a/linux-user/main.c b/linux-user/main.c
index ba09b7d..00810d6 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -4868,6 +4868,11 @@ int main(int argc, char **argv, char **envp)
             env->cp15.sctlr_el[i] |= SCTLR_EE;
         }
 #endif
+
+#if defined(CONFIG_USE_FDPIC)
+        /* Are we running an FDPIC binary?  */
+        env->is_fdpic = info_is_fdpic(info);
+#endif
     }
 #elif defined(TARGET_ARM)
     {
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index 192a0d2..7eaf9e9 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -56,6 +56,8 @@ struct image_info {
         uint16_t        nsegs;
         void           *loadsegs;
         abi_ulong       pt_dynamic_addr;
+        abi_ulong       interpreter_loadmap_addr;
+        abi_ulong       interpreter_pt_dynamic_addr;
         struct image_info *other_info;
 #endif
 };
@@ -182,6 +184,7 @@ abi_ulong loader_build_argptr(int envc, int argc, abi_ulong sp,
 int loader_exec(int fdexec, const char *filename, char **argv, char **envp,
              struct target_pt_regs * regs, struct image_info *infop,
              struct linux_binprm *);
+int info_is_fdpic(struct image_info *info);
 
 uint32_t get_elf_eflags(int fd);
 int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 19a0c03..90c8ee1 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -629,6 +629,12 @@ typedef struct CPUARMState {
     const struct arm_boot_info *boot_info;
     /* Store GICv3CPUState to access from this struct */
     void *gicv3state;
+
+#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)
+    /* We need to know if we have an FDPIC binary to adapt signal
+     * syscalls.  */
+    int is_fdpic;
+#endif
 } CPUARMState;
 
 /**
-- 
2.6.3

On 6 April 2018 at 16:17, Christophe Lyon <christophe.lyon@st.com> wrote:
> Add FDPIC info into image_info structure since interpreter info is on
> stack and needs to be saved to be accessed later on.
>
> Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>
> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
>
> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
> index 7ba3795..363da67 100644
> --- a/linux-user/elfload.c
> +++ b/linux-user/elfload.c
> @@ -287,6 +287,23 @@ static inline void init_thread(struct target_pt_regs *regs,
>      /* For uClinux PIC binaries.  */
>      /* XXX: Linux does this only on ARM with no MMU (do we care ?) */
>      regs->uregs[10] = infop->start_data;
> +#ifdef CONFIG_USE_FDPIC
> +    /* Support ARM FDPIC.  */
> +    /* As described in the ABI document, r7 points to the loadmap info
> +     * prepared by the kernel. If an interpreter is needed, r8 points
> +     * to the interpreter loadmap and r9 points to the interpreter
> +     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and
> +     * r9 points to the main program PT_DYNAMIC info.  */
> +    regs->uregs[7] = infop->loadmap_addr;
> +    if (infop->interpreter_loadmap_addr) {
> +        /* Executable is dynamically loaded.  */
> +        regs->uregs[8] = infop->interpreter_loadmap_addr;
> +        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;
> +    } else {
> +        regs->uregs[8] = 0;
> +        regs->uregs[9] = infop->pt_dynamic_addr;
> +    }

Is it really correct to set these registers always, and not only if
this is an FDPIC ELF ?

> +#endif
>  }

>  int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);
> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
> index 19a0c03..90c8ee1 100644
> --- a/target/arm/cpu.h
> +++ b/target/arm/cpu.h
> @@ -629,6 +629,12 @@ typedef struct CPUARMState {
>      const struct arm_boot_info *boot_info;
>      /* Store GICv3CPUState to access from this struct */
>      void *gicv3state;
> +
> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)
> +    /* We need to know if we have an FDPIC binary to adapt signal
> +     * syscalls.  */
> +    int is_fdpic;

linux-user specific information shouldn't live in CPUARMState;
put it in the TaskState struct instead, perhaps.

> +#endif
>  } CPUARMState;
>
>  /**

thanks
-- PMM

On 13/04/2018 17:07, Peter Maydell wrote:
> On 6 April 2018 at 16:17, Christophe Lyon <christophe.lyon@st.com> wrote:
>> Add FDPIC info into image_info structure since interpreter info is on
>> stack and needs to be saved to be accessed later on.
>>
>> Co-Authored-By:  Mickaël Guêné <mickael.guene@st.com>
>> Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
>>
>> diff --git a/linux-user/elfload.c b/linux-user/elfload.c
>> index 7ba3795..363da67 100644
>> --- a/linux-user/elfload.c
>> +++ b/linux-user/elfload.c
>> @@ -287,6 +287,23 @@ static inline void init_thread(struct target_pt_regs *regs,
>>       /* For uClinux PIC binaries.  */
>>       /* XXX: Linux does this only on ARM with no MMU (do we care ?) */
>>       regs->uregs[10] = infop->start_data;
>> +#ifdef CONFIG_USE_FDPIC
>> +    /* Support ARM FDPIC.  */
>> +    /* As described in the ABI document, r7 points to the loadmap info
>> +     * prepared by the kernel. If an interpreter is needed, r8 points
>> +     * to the interpreter loadmap and r9 points to the interpreter
>> +     * PT_DYNAMIC info. If no interpreter is needed, r8 is zer0, and
>> +     * r9 points to the main program PT_DYNAMIC info.  */
>> +    regs->uregs[7] = infop->loadmap_addr;
>> +    if (infop->interpreter_loadmap_addr) {
>> +        /* Executable is dynamically loaded.  */
>> +        regs->uregs[8] = infop->interpreter_loadmap_addr;
>> +        regs->uregs[9] = infop->interpreter_pt_dynamic_addr;
>> +    } else {
>> +        regs->uregs[8] = 0;
>> +        regs->uregs[9] = infop->pt_dynamic_addr;
>> +    }
> 
> Is it really correct to set these registers always, and not only if
> this is an FDPIC ELF ?
> 
I need to check, but I used my FDPIC-enabled QEMU to run non-FDPIC
binaries and saw no problem.

>> +#endif
>>   }
> 
>>   int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);
>> diff --git a/target/arm/cpu.h b/target/arm/cpu.h
>> index 19a0c03..90c8ee1 100644
>> --- a/target/arm/cpu.h
>> +++ b/target/arm/cpu.h
>> @@ -629,6 +629,12 @@ typedef struct CPUARMState {
>>       const struct arm_boot_info *boot_info;
>>       /* Store GICv3CPUState to access from this struct */
>>       void *gicv3state;
>> +
>> +#if defined(CONFIG_USER_ONLY) && defined(CONFIG_USE_FDPIC)
>> +    /* We need to know if we have an FDPIC binary to adapt signal
>> +     * syscalls.  */
>> +    int is_fdpic;
> 
> linux-user specific information shouldn't live in CPUARMState;
> put it in the TaskState struct instead, perhaps.
> 
OK, I'll have a look at that.

>> +#endif
>>   } CPUARMState;
>>
>>   /**
> 
> thanks
> -- PMM
> .
>